Sliding bearing composite materials consisting of a load bearing substrate and a sliding layer overlay are generally known. The load bearing substrate and the sliding layer are usually connected by laminating using a suitable adhesive. The sliding bearing composite materials can be used to form maintenance free bushing used, for example, by the automotive industry. These maintenance free bushings can be used for door, hood, and engine compartment hinges, seats, steering columns, flywheels, balancer shaft bearings, etc. Additionally, maintenance free bushings formed from the sliding bearing composite materials can also be used in non-automotive applications. In some applications, the sliding bearings are exposed to environmental conditions that lead to corrosion, especially when the load bearing substrate is made of iron alloys, such as steel. There is an ongoing need for improved maintenance free bushings that have a longer maintenance free lifetime and improved delamination resistance or corrosion resistance a high load capability.